ON EVAPORATION AND DISSOCIATION. 
85 
Above the critical point, 193*8°, the compressibility of the substance has been 
given, where its condition may be assumed to approximate to that of a liquid. 
Isothermcds at even 'pressures for 50° and 100°.—As the limits of pressure are so 
small, it has been thought advisable to give these isothermals separately, in order to 
save room. 
Tempera¬ 
ture. 
Pressure. 
Volume of 
1 gramme. 
O 
mms. 
c.cs. 
50 
900 
286-3 
1000 
256-4 
1100 
231-7 
1200 
211-0 
1276 
196-9 
Tempera¬ 
ture. 
Pressure. 
Volume of 
1 gramme. 
0 
mms. 
C.CS. 
100 
2800 
101-1 
3000 
93-67 
3200 
87-18 
3400 
81-45 
3600 
76-32 
3800 
71-74 
Tempera¬ 
ture. 
Pressure. 
Volume of 
1 gramme. 
O 
mms. 
C.CS. 
100 
4000 
67-58 
4200 
63-83 
4400 
60-41 
4600 
57-26 
4800 
54-32 
4859 
53-50 
III. From these results the curve, which we propose to call the orthobaric curve, 
was constructed. It represents the relations between the volumes of a gramme of 
liquid and temperatures, at pressures equal to the vapour-pressures. These were 
obtained by direct reading, sometimes, however, at pressures slightly higher than the 
vapour-pressures; and also from the points of intersection of the curves representing 
compressibility, with the horizontal lines, indicating vapour-pressure. The numbers 
read from the smoothed curve, representing the latter, and also the corresponding 
specific gravities, are given in the following Table 
Tempera¬ 
ture. 
Volume. 
Specific 
gravity. 
Tempera¬ 
ture. 
Volume. 
Specific 
gravity. 
Tempera¬ 
ture. 
Volume. 
Specific 
gravity. 
o 
0 
1-3583 
0-7362 
O 
95 
1-617 
0-6184 
O 
155 
1-976 
0-5061 
40 
] -4505 
0-6894 
100 
1-638 
0-6105 
160 
2-021 
0-4947 
45 
1-4650 
0-6826 
105 
1-660 
0-6024 
165 
2-027 
0-4817 
50 
1-4785 
0-6764 
110 
1-684 
0-5942 
170 
2-147 
0-4658 
55 
1-4900 
0-6711 
115 
1-708 
0-5855 
175 
2-238 
0-4468 
60 
1-5020 
0-6658 
120 
1-735 
0-5764 
180 
2-343 
0-4268 
65 
1-5175 
0-6590 
125 
1-763 
0-5672 
185 
2-489 
0.4018 
70 
1-531 
0-65.32 
130 
1-792 
05580 
190 
2-730 
0-3663 
75 
1-550 
0-6452 
135 
1-823 
0-5485 
192 
2-900 
0-3448 
80 
1-562 
0-6402 
140 
1-857 
0-5385 
193 
3-030 
0-3300 
85 
1-580 
0-6329 
145 
1-893 
0-5283 
90 
1-600 
0-6250 
150 
1-931 
0-5179 
